In the field of thermal ink jet printing, many present manufacturing processes use a chosen thin film processing technique to make the thin film resistor (TFR) substrate portion of the printhead and a separate orifice plate manufacturing technique to make the metal orifice plate having a desired number and geometry of ink ejection orifices therein. Then, using critical alignment techniques, the orifice plate is precisely aligned with the thin film resistor substrate in such a manner that the heater resistors of the TFR substrate are precisely aligned with the orifices in the orifice plate. Thus, the heater resistors are positioned to heat the ink in associated ink reservoirs which are usually aligned with both the heater resistors and the orifices in the orifice plate. In this fashion, the ink is heated to boiling and forced out of the orifices during a thermal ink jet printing operation. One such fabrication process of the type described above is disclosed in the Hewlett-Packard Journal, Vol. 38, Number 5, May 1985, incorporated herein by reference.
While the above Hewlett-Packard process has proven highly successful in most respects, it nevertheless does require the critical alignment between the orifice plate and the thin film resistor substrate, and it further requires separate processing to form the orifice plate and to form the thin film resistor substrate which are subsequently aligned.